The ultimate goal of the proposed project is to significantly improve the effectiveness of jury trials by increasing the probability that jurors will render their verdict in light of the law and not in ignorance of it. In aiming towards this goal, the main objective of this project is to develop an empirical method of producing maximally effective jury instructions, that can be adopted by jurisdictions around the country. During the period of requested support, the project will be aimed at: (1) developing procedures for assessing and rewriting jury instructions until they reach a preset standard of comprehensibility, (2) assessing the comprehensibility of two representative sets of presently used criminal/mental health instructions, (3) manipulating certain psycholinguistic variables that will improve the perception, memory, and comprehension of these instructions, and (4) demonstrating that the new rewritten instructions are maximally effective both after being heard and during the jury deliberations. After demonstrating the efficacy of the empirical method developed during the project, the staff will write a manual designed to provide drafting committees with easy to follow instructions on how to use this method in their own jurisdictions. Support for writing, producing and distributing the manual will not be requested until the completion of this project.